Poor Spark

I recently replaced the coil on my ST70 as I was getting no sparks. The replacement is a genuine Honda unit, which I have made sure of a good earth. I don't want to have to go through removing it again! All was well at first, getting plenty of sparks, fuel and she ran well. However, I'm back with what seems to be the same problem ie poor sparking. I have checked the generator by attaching a bulb to the output cable and it does light up as it should but by no means every kick. The timing, plug, points and condenser seem fine and I have not found any loose connections. I have noticed that leaving the bike at rest for say half an hour usually restores the spark, but after a few kicks they start to fade. I have run out of ideas so any help would be much appreciated.

Hi did you sort the problem as I'm having the same trouble

Have you check the condensor

Measure the resistance of the ignition coil ,the resistance of the primary and secondary ht coil
Tell me what they measure.

Could be a number of things ,I would check the following
Resistance or the condensor
Points gap and check they are clean and correct position.
Ignition coil resistance around 2.1 ohms
Primary coil around 2 ohms
Secondary coil around 9Mohms
Insulation resistance on the coils want to be above 1 M ohm
No earth to coil when ignition switch is in the on position
Hope this helps